PCA9555AHF,128

I/o Expanders Overview

The PCA9555AHF,128 is a low-voltage 16-bit General Purpose Input/Output (GPIO) expander designed for I2C-bus and SMBus applications. It operates within a supply voltage range of 1.65 V to 5.5 V and supports Fast-mode clock frequencies up to 400 kHz. The device features an open-drain active LOW interrupt output and includes weak pull-up resistors on all input/output pins. It provides 25 mA sink drive capability for direct LED driving and offers Schmitt-trigger action on SCL and SDA inputs for improved noise immunity. The component is housed in a 24-terminal HWQFN package.

I/o Expanders Feature Summary

• Provides 16-bit GPIO expansion with individual pin configuration as high-impedance inputs or outputs via Configuration registers.
• Features an open-drain interrupt output that activates when any input state differs from its corresponding Input Port register state.
• Includes internal weak pull-up resistors on all I/O pins to eliminate the need for external components.
• Supports hardware-selectable slave addresses using three address pins, allowing up to eight devices on a single bus.

I/o Expanders Applications

• ACPI power switches
• Sensor interface connections
• Push button expansion
• LED driver circuits
• Fan control systems

I/o Expanders Procurement Notes

Verify the specific ordering suffix ',128' corresponds to the HWQFN24 package and reel packing method before procurement. Confirm that the required operating temperature range of -40 °C to +85 °C aligns with the application environment. Ensure the system design accounts for the 25 mA maximum sink current capability per output pin to prevent exceeding device limits.

I/o Expanders Selection Notes

Select this component when a 16-bit I/O expansion solution is required for I2C-based systems. It serves as a pin-to-pin replacement for the PCA9555 but requires software adjustments due to enhanced features. For designs requiring Agile I/O capabilities, consider the PCAL9555A instead. Verify that the 1.65 V to 5.5 V supply voltage range matches the target microprocessor or microcontroller logic levels.

I/o Expanders Part Context

The PCA9555AHF,128 belongs to the PCA9555A series of I/O expanders developed by NXP Semiconductors. It is part of the broader family of I2C-bus I/O expanders designed to enhance standard parallel port expansion. This specific variant utilizes the HWQFN24 package, offering a compact form factor suitable for space-constrained printed circuit board layouts while maintaining thermal performance through an exposed center pad.

I/o Expanders Replacement Considerations

The PCA9555AHF,128 is a pin-to-pin replacement for the PCA9555. However, software changes are required due to the enhanced features of the A-series. The PCAL9555A is available as a more fully featured alternative with Agile I/O capabilities.